The present invention relates to a method for determining the alignment of a laser light beam referred to an axis of rotation of a device that is rotatable around the axis of rotation, wherein the alignment is ascertained by means of a laser light detection device, and the laser light detection device.
Known methods and laser light detection devices for determining the alignment of a laser light beam referred to an axis of rotation of a device which can rotate about the latter, such as a roller or a shaft, are used in particular to determine the alignment of the axis of rotation in relation to a reference direction or a reference axis which can also run parallel to the laser light beam or be aligned with it. In particular, on the basis of such methods, one can determine, for example, the alignment of the rolls of a rolling mill with each other, in order to identify any deviations from a desired parallel orientation of the axes of rotation of the rolls. Thus, e.g., from EP 0 518 572 A2, it is known how to install or arrange at least one laser light sensor on the periphery of at least one of the rolls in a layout composed of several rolls, or with a radial spacing of the rolls, or with a distance from the roll measured perpendicular to the axis of rotation. Such an arrangement of laser light sensors on a roller or shaft is also known from DE 39 11 370 A1. However, there are limits to the determination of the alignment of a laser light beam in this arrangement, when such is not possible due to particular structural features. One can imagine, e.g., a rolling stand whose rolls are surrounded by a protective covering so that the covering surface area of the rolls is not accessible from outside the rolling stand. Moreover, there are rolling stands—such as in the paper industry—that are partly or totally housed or whose rolls are set very close together or whose roll surface is not suited to the mounting of the laser light sensors, e.g., due to a conical configuration of the rolls or due to a rubberized or closed or too small a configuration of the roll surface.
Other methods for determining the alignment of devices based on lasers and/or detectors are known, for example, from DE 10 2008 035 480 A1, DE 101 09 462 A1, DE 10 2009 026 836 A1, DE 10 2011 078 623 A1, DE 10 2007 041 750 A1, EP 0 474 799 B1, U.S. Pat. No. 3,923,402 and DE 38 14 466 A1. A method for determining the alignment of mechanisms on the basis of a measuring device and a target mark is known from DE 10 2004 004 412 A1.